Solar Cell Efficiency Breakthrough Achieved By Channeling LEGO

Chalk up another score for aluminum. The humble — as in, cheap and abundant — metal has been popping up all over the sustainable tech field, and in the latest development, an international research team has demonstrated that nanoscale LEGO-style array of aluminum studs can improve solar cell efficiency by up to 22 percent. If the labwork translates into commercial development, that will help drive the rapidly sinking cost of solar power down even farther.

That’s a significant breakthrough, because until now gold and silver have been the focus of attention in the solar cell efficiency field due to their vigorous interaction with light.

However, the research team, spearheaded by Imperial College in London, compared the results of their LEGO-style aluminum array with identical arrays made of gold and silver. They found that the more expensive metals did not boost solar cell efficiency as much as aluminum, and in fact resulted in reduced efficiency.

How A LEGO-Like Array Builds Solar Cell Efficiency

The new research was recently published in the journal Nature under the mouthful “Loss mitigation in plasmonic solar cells: aluminium nanoparticles for broadband photocurrent enhancements in GaAs photodiodes.”

The idea behind the nanoscale LEGO studs is to force light to bend, enabling layers of energy-absorbing material to trap more solar energy.

That reduces the amount of absorbing material needed, which in turn helps to lower the cost of production.

The team tested their LEGO studs on thin film gallium arsenide solar cells. Writer Simon Levey of Imperial College describes it like this:

Dr Hylton and his colleagues attached rows of aluminium cylinders just 100 nanometres across to the top of the solar panel, where they interact with passing light, causing individual light rays to change course. More energy is extracted from the light as the rays become effectively trapped inside the solar panel and travel for longer distances through its absorbing layer.

As for the key factor that enables aluminum to vault over gold and silver, the precious metals tend to absorb light into themselves.

Aluminum, in contrast, simply bends and scatters light, passing it along to the solar cell. As an added advantage, its light weight and flexibility make it compatible with the new generation of flexible solar cells.

Aluminum And Sustainable Technology

Precious metals and rare earths get a lot of the headlines in solar cell tech, but aluminum has been steadily gaining under the radar.

This is the first example we’ve covered that involves integrating aluminum into a solar cell, but there are a growing number of examples of aluminum used in solar modules.

Aluminum is also making headway in the transportation field. Aside from contributing to lighter and thereby more fuel efficient vehicles, researchers are checking out its potential use in metal-air batteries.